← All compounds · evidence tier first, by design

Evidence tier for each claimed use · ← established · unknown →
Use	E1	E2	E3	E4	E5	E6	E7	E8
E6 Cognitive enhancement / dementia						E6

Class C · Gray market

Dihexa

N-hexanoic-Tyr-Ile-(6) aminohexanoic amide: a modified dipeptide (Tyr-Ile) with an N-terminal hexanoyl group and a C-terminal 6-aminohexanoic amide; non-standard groups, so no one-letter sequence is given.

Non-standard residues or modifications: no plain one-letter sequence

Also: Dihexa acetate, N-hexanoic-Tyr-Ile-(6) aminohexanoic amide

A small, chemically modified peptide derived from angiotensin IV, designed at a US university to be stable and to reach the brain when taken by mouth. It is sold online as a research chemical with claims of improving memory and cognition. It has never been tested in people in any published study identified, and no approved medicine contains it. Two journal papers from the developing laboratory on the angiotensin IV/HGF approach were retracted in 2025, and the original dihexa report carries an expression of concern.

US C gray market
EU C gray market
UK ? not verified
CA C gray market
AU ? not verified
JP ? not verified
CN ? not verified

01Regulatory status, by jurisdiction

Standing notice. This compound is not approved as a medicine in any jurisdiction tracked here and has no active sponsor seeking approval. Material sold under this name, typically labelled “research chemical, not for human consumption”, is of unverified identity and purity and is not manufactured to pharmaceutical standards.

Jurisdiction	Status	Detail and primary source
US	Not approved	No FDA-approved application: openFDA Drugs@FDA returns no application with a dihexa active ingredient (query: products.active_ingredients.name:DIHEXA*). openFDA states its data are unvalidated. “No matches found!” openFDA Drugs@FDA API (FDA) · retrieved 2026-10-10
US	Not approved	Dihexa acetate appears on FDA's list of bulk drug substances previously in Category 2 (significant safety risks) of the compounding interim policy whose nominations were withdrawn by the nominators. FDA's safety statement remains on the page. “FDA has not identified any human exposure data on drug products containing dihexa acetate administered via any route of administration.” Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of 04/22/2026) · retrieved 2026-10-10
EU	Not approved	No product containing dihexa appears in EMA's downloadable medicines dataset (generated 10 Oct 2026), which covers centrally authorised medicines, refusals and withdrawn applications. National authorisations were not checked individually. “This includes information on marketing authorisations of centrally authorised medicines and post-authorisation procedures.” Download medicine data \| European Medicines Agency (EMA) · retrieved 2026-10-10
CA	Not approved	A query of Health Canada's Drug Product Database API for the active ingredient dihexa returned no products on the retrieval date; a brand-name query matched only unrelated veterinary teat-dip products whose names begin with the same letters. “Search by drug identification number” Drug Product Database online query · retrieved 2026-10-10
UK AU JP CN	Not yet verified from a primary source. No status is shown rather than an unsourced one.

Sport (WADA): Prohibited · class S0. Dihexa is not named on the 2026 Prohibited List; as a substance with no governmental approval for human use identified, it falls under class S0. “Any pharmacological substance which is not addressed by any of the subsequent sections of the List and with no current approval by any governmental regulatory health authority for human therapeutic use” WADA source

02What the human evidence shows

Cognitive enhancement / dementia

No human trial of any design has been published for this use.

0published human RCTs

0published human trials

0registered studies

0with posted results

All efficacy data are from rodents. The developing group reported that dihexa reversed scopolamine-induced and age-related deficits in a water-maze test in rats; the journal attached an expression of concern to that report in 2021. A separate group reported improved spatial learning in APP/PS1 Alzheimer-model mice. A 2014 paper from the developing laboratory proposing that these effects depend on the HGF/c-Met system was retracted in 2025. No human study of any kind was identified.

[1] Reversed scopolamine-induced and age-related water-maze deficits in rats (report subject to a 2021 expression of concern)
[2] Improved spatial learning in the water maze and reduced glial activation in APP/PS1 Alzheimer-model mice
[3] Retraction of the 2014 rodent and cell report linking these peptides' effects to the HGF/c-Met system

Registered-study counts: ClinicalTrials.gov intervention search “dihexa”, fetched 2026-10-10. Registered studies include trials of other uses; the gap between registered and reported is itself a finding.

03Safety signals

S5No human safety data

There are no adequate human safety data. The absence of reported harm is not evidence of safety.

04What is unknown

No human data of any kind were identified: no pharmacokinetic, safety or efficacy study in people
FDA states it has not identified any human exposure data and lacks information on whether dihexa would cause harm in humans
The proposed mechanism through hepatocyte growth factor and its receptor c-Met is a pathway also involved in cell growth and cancer; long-term effects of stimulating it in humans are unstudied
Independent replication of the original rat findings is limited to one mouse study identified, and the founding reports are under an expression of concern or retracted
Status in the UK, Australia, Japan and China was not verified from regulator sources for this record

05Product quality

No independent purity results have been published for this compound yet. The purity programme will publish full methods and vendor-named results, passes and failures, once its protocol has had legal review.

06Citations

Evaluation of Metabolically Stabilized Angiotensin IV Analogs as Procognitive/Antidementia Agents (2013). doi:10.1124/jpet.112.199497
AngIV-Analog Dihexa Rescues Cognitive Impairment and Recovers Memory in the APP/PS1 Mouse via the PI3K/AKT Signaling Pathway (2021). doi:10.3390/brainsci11111487
Retraction notice to “The Procognitive and Synaptogenic Effects of Angiotensin IV–Derived Peptides Are Dependent on Activation of the Hepatocyte Growth Factor/c-Met System” [J Pharmacol Exp Ther 351 (2014) 390-402] (2025). doi:10.1016/j.jpet.2025.103567

Every DOI is resolved against Crossref and every NCT number against ClinicalTrials.gov, title for title, before publication. Regulatory sources are cited inline above with a verbatim quote and retrieval date.

07Mechanism

Dihexa was derived from angiotensin IV. Its developers proposed that it acts by enhancing hepatocyte growth factor signalling through the c-Met receptor; a key 2014 paper supporting that mechanism has been retracted, so the mechanism is not established.

Mechanism is placed last on purpose: a plausible mechanism is not evidence that a compound works in people.

Reviewed by OSMF research team (AI-assisted, source-verified) on 2026-10-10. Found an error? It goes in the corrections log: report it.